This is how Trump left the White House for Walter Reed Hospital 0:32
(CNN) -
Hydroxychloroquine, the malaria drug that President Donald Trump has said he took in hopes of protecting himself from COVID-19, did not prevent infections among volunteers in a study published Wednesday.
The study, which was completed early, included 125 healthcare workers.
Some of them took hydroxychloroquine daily for eight weeks, while others took a placebo.
"There was no significant difference in infection rates in participants randomized to receive hydroxychloroquine compared to (those who received the) placebo," the researchers wrote in the study published in the journal
JAMA Internal Medicine
.
Study: hydroxychloroquine does not help treat covid-19 1:12
Based on their findings, the University of Pennsylvania researchers wrote that they cannot "recommend the routine use of hydroxychloroquine" among healthcare workers to prevent COVID-19.
LEE: Donald Trump has covid-19: how serious is his risk?
Participants were enrolled in the new study from April to July.
The investigation found that four of the 64 healthcare workers who received hydroxychloroquine ended up testing positive for COVID-19.
For their part, four of the 61 workers who received a placebo tested positive.
Among the eight participants who tested positive, six developed symptoms.
None required hospitalization and all recovered clinically from the disease, according to the study.
Broadly speaking, the new research's findings are similar to those of another study that was published in the
New England Journal of Medicine
in June.
That earlier study found that hydroxychloroquine does not prevent illness when used within four days of exposure to the coronavirus that causes covid-19.
The White House had requested information on hydroxychloroquine
In June, Dr. David Boulware, the author of that earlier study, told CNN that the president's doctor sent him an email on May 9 seeking his opinion on using the drug preventively.
He also asked about the research results and the doses that the study subjects were taking.
Boulware said that he informed Trump's doctor that there was no published research showing hydroxychloroquine working preventively.
He also shared that the people in his study who took hydroxychloroquine had higher rates of side effects.
Among these were mainly gastrointestinal problems such as nausea and vomiting.
READ: Minute by minute: the health of Donald and Melania Trump
"I knew they were probably going to ignore what I said because the White House had been talking about hydroxychloroquine for weeks, weeks and weeks," Boulware said.
The doctor is an expert in infectious diseases and a professor of medicine at the University of Minnesota.
"Even in the context of a pandemic, we need research to help inform best practice of what works in humans," Boulware said.
In July, the US Food and Drug Administration revoked an emergency use authorization for hydroxychloroquine and chloroquine to treat COVID-19.
The agency now says that hydroxychloroquine and chloroquine have not been shown to be safe and effective in treating or preventing the disease.
CNN's Elizabeth Cohen contributed to this report.
covid-19 Hydroxychloroquine